AD Power Co. - Products include standby power meters (such as Wattman HPM-100), oscilloscopes, spectrum analyzers, DC power supplies and other instruments.
Basics of High Voltage Probe Design - Covers theory, tips, pratical advice, sources, parts, links to other sites, and information about HV probes uses and design.
Rectifiers and Electronics - Manufacturers of AC/DC high voltage and high current testing equipments, spark testers, industrial voltage stabilizers, AC and DC welding equipment, battery chargers. New Delhi, India.
Vitrek - Manufactures high potential testers for both AC and DC measurements including a complete ground safety, fault locating, and measurement systems.